Process of bluing iron or steel articles.



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PROCESS OF BLUING IRON OB. STEEL ARTICLES. APPLICATION FILED mm: 2, 1909.

Mnvzsszs; fle 2 LIA To all whom 'it may concern:

-rrnp srars PATENT err-ten MORGAN anus, or FOLLANSBEE, wizs'r )VIRGINIA, ASSIGNOR or ONE-THIRD TO WILLIAM A. SKINKLE, OF

CLEVELAND, OHIO, AND ONE-THIRD TO WILLIAM THOMAS, OF PITTSBURG, V PENNSYLVANIA.

PROCESS OF BLUING IRON OR STEEL ARTICLES.

9&9500.

Be it knownthat- I, MORGAN Runs, a Brit- 4 ishsubject but about to become a citizen of I the United States, residing at Follansbee,

Brooke county, Vest Virginia,have invented certain new and useful Improvements in Processes for Bluing Iron and Steel Articles,

of which the following is a specification, I I

have time to circulate through the pile of that. will enable those skilled in the art to which the invention pertains to practice the same, reference being had to the accompanyingdrawing, which forms a part hereof.

This invention relates to an improved process for bluing articles of iron or steel, whereby the same attain a deep blue color, and it is particularly applicable to sheets or plates of such metals vwhich, when polished by cold rolling or otherwise, become similar to what is knownin commerce as Russian sheet iron. A

For a full understanding of the invention and the merits thereof, reference is to be had to the accompanying drawing, which is a vertical section through one form of device for carrying on the bluing process.

This drawing shows a form of apparatus that is now considered desirable, but obviously, many changes, not requiring the ex- ,ercise of invention, might be made in the details thereof by a skilful mechanic, with out materially changing the essential features of the process and without departure from the spirit of the invention as set forth in the claims at the end of this specification.

To put the invention into practice, by a method which has been followed with success in the bluing of sheets, for which itis particularly designed, the sheets or plates of iron or steel, astaken from the rollsor hammers, are first pickled in a mixture of sulfuric acid and other ingredients in the manner well known in the art, to remove the scale. After being thus pickled the plates are, preferably, annealed by piling them one uppn the other on an annealing box bottom 1, a metal cover 2, being placed upon the bottom 1, to inclose the plates, the whole then placed in an annealing furnace and heated to a high temperature, say about 1600 to 1800 degrees, Fahrenheit. ,The box and contents are removed from the furnace and allowed to stand for several hours and cool down gradually to about (300 to 700 degrees, Fahrenheit.

v i l 1 herein described.

Specification of Letters Patent. Patented Feb. 15, 191() Application filed June 2, 1909. Serial No. 499,710.

It is important that the temperature be lowered to about this condition as it is the temperature which has been found best suited to promote the desired action of the particular gases and the steam in the bluing process A much higher temperature than 700 degrees would probably be destructive to these gases before they would plates and perform their coloring functions, while a much lower temperature than (300 degrees would not be sutlicient to properly vaporize the chemicals.

In common practice the annealing box bottom and cover are heavy, rough iron castings and the joint between them is unfinished and rough. As this joint is not tight it is customary to form a seal 3 of fine dry sand, piled several inches deep all around the joint, which seal, while not-absolutely tight against the forced passage of air or gas under pressure, is enough to prevent the passage of air or gas under normal atmosphere and to sufficiently protect the inclosed plates against undesirable exposure.

The annealing box 2 is fitted with steam connection pipe and valve 5, which may be located at any convenient point, and the pipe is connected by a suitable coupling (5 and pipe 7 to a convenientform of device for introducing the chemicals, in powdered form, into the interior of the annealing box 2 in conjunction with the steam. The chemicals, ,which are thus carried into the annealing box by the steam passing through connection 5 are sulfur and charcoal or carbon, preferably, in powdered form, in about equal proportions, from three to four ounces of them being used to four to five tons of steel or iron plates.

The device for holding the chemicals,

which may be mixed, if desired, to form a powdered composition, consists of a box 8 having asteam inlet pipe 9 entering the same, the said pipe being formed with a down into the path of the steam jet and be forced along with the steam or moisture into the annealing box 2. In .the construction shown on the drawing the compartment 12 is formed with a perforated bottom 14 and a perforated plate 13 rests upon the bottom and cooperates therewith to regulate therated bottom" of the compartment upon the inclined plate 15 are carriedby the steam into the interior of the annealing box so as to act upon the plates therein.

Steam alone may be let into the annealing box by way of the pipe 17.

When the annealing box is closed over the pile of plates the considerable unoccupied spaces are filled with air, which, when subjected to the heat of the annealing, expands and causes a slight pressure under which some of the air will escape by seeping out through the sand seal. When the box, after withdrawal from the annealing furnace, is cooling down the remainin air in it will contract and thus create a sight vacuum, to relieve which some outside air will seep back, through the hot sand seal,

into the box.

Another method of using the powdered ingredients is to remove from several places or spots the sand forming the seal3 between the bottom 1 and the box 2 and to place the powder in these bared spaces close against the side of the cover and adjacent to the joint opening, then return the hot sand upon the top of the powder, and moisten the sandwith water. The powdered sulfur and carbon thus placed will be converted into gases and the water into steam by their hot environment, and these will be drawn into the box through the joint by reason of the Vacuum caused by the continued cooling and contraction of the air within; The gases and steam thus find their way into the box where there is already a quantity of air with which they commingle and circulate around and through the pile of plates. A jet of live steam may also be used at this juncture with good effect to give additional moisture to the gaseous mixture and to agitate and quicken it into more active circulation about and through the plates. The sulfur and carbon are used in powdered'form only for the convenience of the operator in handling them with this form of apparatus, but it will be obvious that immediately upon their entrance into the box they meet with the heated airalready in the box or come into contact with the heated metal of the box or with the pile of heated plates therein and are at once converted into gases, which to-. gether with the steam attack the. surfaces of the plates and ive them a deep blue color. It will be understood, therefore, that it is the hot sulfur and carbon gases together with the moisture of the steam and the hot air already in the box that do the bluing of the plates; and that with suitable appalatitude may be had in this respect without materially affecting the result and that no very hard and fast rule need be followed.

After the introduction of sufficient chem icals, or their gases, and the steam the box is allowed to remain closed for a number of hours untilit and the'plates within it have cooled down slowly to about the normal temperature of the outer air, when the b1u-.

ing process is finished.

The sheets, when taken from the box will have a deep blue color over their entire surfaces, and should it be desired to polish the plates, the cold rolling process is used in the manner well known in the art.

Care should be taken that the box he kept "closed and the plates not exposed to the cold outside air at any stage of the process and that no outer air be admitted to the box ex cept, perhaps, such small quantity as may seep or be drawn in through the seal of hot sand during the cooling down period.

In the foregoing I have described the process as practiced with an annealing box, and this will, doubtless, be the most usual manner of practicing it as mostplate-finish- .ing mills anneal their plates and are, therefore, already provided with suitable boxes.

-Pre-annealing, however, is not essential for the practice of this invention, and the bluing may be carried on in any suitable closed vessel, oven, chamber or receptacle in which -the plates may be heated without exposure to the direct action of the furnace fire. It has also been describcdthat the plates are first subjected to the high temperature, 1600 to 1800'degrees Fahrenheit, necessary in the annealing process, but cold and un-annealed plates may be blued by simply heating them in a closed receptacle up to about 650 degrees, Fahrenheit, which has been found to be about right for this process of bluing.

Pickling, to remove the scale and other in'lpurities from the surfaces of the plates, while not a step in this invention, is quite necessary for the production of finely finished plates and it should always be done before the bluing process for finished work. While the process has been described, herein, in its application to bluing iron and steel plates or sheets, it is notmeant to limit its use to these for'msfor, as will be readily understood, it is equally applicable to blueaeeoo,

ing the surfaces of other forms of iron or steel articles.

Having thus described the invention, What is claimed as neW-is:-

1. The process of bluing iron or steel articles which consists of placing said articles in a closed receptacle, heating and subjecting them to the action of sulfur and carbon gases together With steam and the heated air already in the receptacle.

2. The process of bluing iron or steel articles which consists of placing said articles in a closed receptacle and heatin them to about 650 degrees, Fahrenheit, an then subjecting them to the action of sulfur and carbon gases together with steam and the heated air already in the receptacle.

3. The process of bluing iron or steel articles which consists of placing them in a closed receptacle and heating them to about 650 degrees, Fahrenheit, then injecting first sulfur and carbon gases into the receptacle and later a jet of steam.

4. The process of bluin iron or steel articles which consists of p acing them in a closed receptacle, heating them and subjecting them to the'action of sulfur and carbon gases and steam together with the heated air already in the receptacle and then allowing them to cool in the closed receptacle.

In testimony whereof I have signed my name to this specification in the presence of.

two subscribing witnesses.

MORGAN REES.

Witnesses:

TREVOR THoMAs. ALBERT JAMES. 

